Method for inspecting a reticle, a method for manufacturing a reticle, and a method for manufacturing a semiconductor device using the same

ABSTRACT

A method for inspecting a reticle including a reflective layer on a reticle substrate is provided. The method may include loading the reticle on a stage, cooling the reticle substrate to a temperature lower than a room temperature, irradiating a laser beam to the reflective layer on the reticle substrate, receiving the laser beam using a photodetector to obtain an image of the reflective layer, and detect a particle defect on the reflective layer or a void defect in the reflective layer based on the image of the reflective layer.

CROSS-REFERENCE TO RELATED APPLICATION

This U.S. non-provisional patent application claims priority under 35U.S.C. § 119 to Korean Patent Application No. 10-2019-0093406, filed onJul. 31, 2019, in the Korean Intellectual Property Office, thedisclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

Embodiments of the inventive concepts relate to a method formanufacturing a semiconductor device, and more particularly, to a methodfor inspecting a reticle, a method for manufacturing a reticle, and amethod for manufacturing a semiconductor device using the same.

Highly integrated semiconductor devices have been developed with thedevelopment of information technology. The integration density ofsemiconductor devices may be greatly affected by a wavelength of a lightsource of a photolithography process. The light source may be an I-linesource, a G-line source, an excimer laser light source (e.g., KrF orArF), or an extreme ultraviolet (EUV) light source of which a wavelengthis shorter than that of the excimer laser light source. The photonenergy of the EUV light source may be much greater than that of theexcimer laser light source. The EUV light source may cause particlecontamination and damage of an EUV reticle. The contaminated EUV reticlemay be replaced with a new one or may be cleaned. The damaged EUVreticle may be replaced with a new one.

SUMMARY

Embodiments of the inventive concepts may provide a method forinspecting a reticle which is capable of increasing a signal-to-noiseratio of optical inspection and of minimizing damage of the reticle, amethod for manufacturing a reticle, and a method for manufacturing asemiconductor device using the same.

In an aspect, a method for inspecting a reticle is provided. The reticlemay include a reflective layer on a reticle substrate. The method mayinclude loading the reticle on a stage, cooling the reticle substrate toa temperature lower than a room temperature, irradiating a laser beam tothe reflective layer on the reticle substrate, receiving the laser beamusing a photodetector to obtain an image of the reflective layer, and todetecting whether a particle defect exists on the reflective layer or avoid defect exists in the reflective layer based on the image of thereflective layer.

In an aspect, a method for manufacturing a reticle may include forming areflective layer on a reticle substrate and inspecting the reflectivelayer. The inspecting the reflective layer may include cooling thereticle substrate to a temperature lower than a room temperature,irradiating a laser beam to the reflective layer, receiving the laserbeam using a photodetector obtain an image of the reflective layer, anddetecting whether a defect in the reflective layer exists based on theimage of the reflective layer.

In an aspect, a method for manufacturing a semiconductor device mayinclude performing an exposure process using a reticle, inspecting thereticle, and storing the reticle. The reticle may include a reticlesubstrate, a reflective layer on the reticle substrate, and anabsorption pattern on the reflective layer. The inspecting the reticlemay include cooling the reticle substrate to a temperature lower than aroom temperature, irradiating a laser beam to the reflective layer andthe absorption pattern on the substrate, receiving the laser beam usinga photodetector to obtain an image of the reflective layer and theabsorption pattern, and detecting whether a particle exists on thereflective layer or on the absorption pattern, based on the image of thereflective layer and the absorption pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concepts will become more apparent in view of the attacheddrawings and accompanying detailed description.

FIG. 1 is a block diagram illustrating an apparatus for manufacturing asemiconductor device, according to some embodiments of the inventiveconcepts.

FIG. 2 is a schematic view illustrating an embodiment of an exposureapparatus of FIG. 1.

FIG. 3 is a cross-sectional view illustrating an embodiment of a reticleof FIG. 2.

FIG. 4 is a block diagram illustrating an embodiment of a reticleinspecting apparatus of FIG. 1.

FIG. 5 is a cross-sectional view illustrating an example of the reticleinspecting module of FIG. 4 according to an embodiment.

FIG. 6 is a graph showing a heat capacity of a reflective layer and anincrease rate of second laser beam power, according to a temperature ofthe reticle of FIG. 2.

FIG. 7 is a cross-sectional view illustrating an example of the reticleinspecting module of FIG. 4 according to an embodiment.

FIG. 8 is a cross-sectional view illustrating an embodiment of a reticlecleaning module of FIG. 4.

FIG. 9 is a flowchart illustrating a method for manufacturing asemiconductor device, according to some embodiments of the inventiveconcepts.

FIG. 10 is a flowchart illustrating a method for manufacturing thereticle of FIG. 2, according to some embodiments of the inventiveconcepts.

FIGS. 11 to 13 are process cross-sectional views of the reticle of FIG.3.

FIG. 14 is a flowchart illustrating a method for inspecting a reflectivelayer of FIG. 3, according to some embodiments of the inventiveconcepts.

FIG. 15 is a flowchart illustrating a method for inspecting aphotoresist of FIG. 13, according to some embodiments of the inventiveconcepts.

FIG. 16 is a flowchart illustrating a method for inspecting the reticleof FIG. 3, according to some embodiments of the inventive concepts.

FIG. 17 is an example of a scattering intensity profile of an imagegenerated by a reticle inspecting apparatus according to someembodiments of the inventive concepts.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 illustrates an apparatus 100 for manufacturing a semiconductordevice, according to some embodiments of the inventive concepts.

Referring to FIG. 1, an apparatus 100 for manufacturing a semiconductordevice according to some embodiments of the inventive concepts may be aphotolithography apparatus. The manufacturing apparatus 100 may be usedto form a photoresist pattern on a substrate W. In some embodiments, themanufacturing apparatus 100 may include a spinner apparatus 10, anexposure apparatus 20, a reticle manufacturing apparatus 30, a reticleinspecting apparatus 40, and a reticle storing apparatus 50.

The spinner apparatus 10 may be disposed adjacent to the exposureapparatus 20. A substrate W may be transferred between the spinnerapparatus 10 and the exposure apparatus 20. The substrate W may includea semiconductor wafer, such as a silicon wafer. The spinner apparatus 10and the exposure apparatus 20 may form a photoresist pattern on thesubstrate W. The spinner apparatus 10 may perform a coating process, abake process and a development process of a photoresist. The exposureapparatus 20 may perform an exposure process of the photoresist by usinga reticle R. For example, the exposure apparatus 20 may be an extremeultraviolet (EUV) exposure apparatus, and the reticle R may be an EUVreticle. In some embodiments, the spinner apparatus 10 may include achuck for holding the wafer, one or more nozzles for performing thecoating process and delivering chemicals during the developing processand a heater (e.g., heater plate) for performing the bake process.

The reticle manufacturing apparatus 30 may be used to manufacture thereticle R. Even though not shown in the drawings, the reticlemanufacturing apparatus 30 may include a thin layer depositing module, aphotoresist coating module, a photolithography module, an etchingmodule, and a cleaning module. The thin layer depositing module may beused to deposit a thin layer (e.g., a silicon layer, a molybdenum layer,and/or an absorption layer) on a reticle substrate 2 (see FIG. 11). Thephotoresist coating module may be used to coat the reticle substrate 2with a photoresist PR (see FIG. 11). The photolithography module may beused to pattern the coated photoresist PR. The etching module may beused to etch the thin layer (e.g., the absorption layer) along thepatterned photoresist PR.

The reticle inspecting apparatus 40 may be disposed between the exposureapparatus 20 and the reticle storing apparatus 50. The reticleinspecting apparatus 40 may be used to inspect the reticle R. Forexample, the reticle inspecting apparatus 40 may detect a defect (e.g.,a particle 8 of FIG. 5 and/or a void 9 of FIG. 11) of the reticle R.

The reticle storing apparatus 50 may store the reticle R temporarilyand/or for a long time. The reticle R may be transferred to the exposureapparatus 20, the reticle manufacturing apparatus 30, the reticleinspecting apparatus 40, or the reticle storing apparatus 50 while beingloaded in a reticle pod.

FIG. 2 illustrates an embodiment of the exposure apparatus 20 of FIG. 1.

Referring to FIG. 2, the exposure apparatus 20 may include an EUVscanner or an EUV stepper. For example, the exposure apparatus 20 mayinclude a chamber 210, an EUV source 220, an optical system 230, a firstreticle stage 240, a substrate stage 250, and a rapid exchange device260.

The chamber 210 may provide an inner space into which the substrate Wand the reticle R are loaded. The inner space of the chamber 210 may beindependent of the outside when a process is performed. For example, thechamber 210 may have a vacuum pressure of, for example, 1×10⁻⁴ Torr to1×10⁻⁶ Torr. When a gas (e.g., hydrogen) is injected into the chamber210, the chamber 210 may have an inner pressure of, for example, 1×10⁻²Torr to 1×10⁻⁴ Torr. The chamber 210 may include a main chamber 212 andan auxiliary chamber 214. The main chamber 212 may surround the EUVsource 220, the optical system 230, the first reticle stage 240, and thesubstrate stage 250. The auxiliary chamber 214 may be connected to aside of the main chamber 212. The auxiliary chamber 214 may temporarilystore the reticle R.

The EUV source 220 may be disposed in one side portion of the mainchamber 212. The EUV source 220 may generate an EUV beam 22. The EUVbeam 22 may be a plasma beam. In some embodiments, the EUV source 220may include a source drop generator 222, a first laser 224, and acollector mirror 226. The source drop generator 222 may generate asource drop 221. The source drop 221 may include a metal liquid drop oftin (Sn), xenon (Xe), titanium (Ti) or lithium (Li). The first laser 224may irradiate a first laser beam 223 to the source drop 221 to generatethe EUV beam 22. The first laser beam 223 may be pump light of the EUVbeam 22. An intensity of the EUV beam 22 may be in proportion to anintensity or power of the first laser beam 223. The collector mirror 226may focus or concentrate the EUV beam 22 to the optical system 230. Forexample, the collector mirror 226 may include a concave mirror.

The optical system 230 may be disposed between the first reticle stage240 and the substrate stage 250. The optical system 230 may sequentiallyprovide the EUV beam 22 to the reticle R and the substrate W. Forexample, the optical system 230 may include a field facet mirror 232, apupil facet mirror 234, a grazing mirror 236, and projection mirrors238. The field facet mirror 232, the pupil facet mirror 234 and thegrazing mirror 236 may be used as an illumination system for providingthe EUV beam 22 to the reticle R. The field facet mirror 232 may reflectthe EUV beam 22 to the pupil facet mirror 234. The pupil facet mirror234 may reflect the EUV beam 22 toward the reticle R. The field facetmirror 232 and the pupil facet mirror 234 may collimate the EUV beam 22.The grazing mirror 236 may be disposed between the pupil facet mirror234 and the reticle R. The grazing mirror 236 may adjust a grazingincident angle of the EUV beam 22. The projection mirrors 238 may beused as a projection objective for providing the EUV beam 22 to thesubstrate W. The projection mirrors 238 may provide the EUV beam 22 tothe substrate W.

The first reticle stage 240 may be disposed in an upper region of theinner space of the main chamber 212. The first reticle stage 240 mayhave a reticle chuck 242. The reticle chuck 242 may electrostaticallyhold the reticle R by using an electrostatic voltage. For example, thereticle R may be a reflective mask. The reticle R may reflect a portionof the EUV beam 22 to the projection mirrors 238 and may absorb anotherportion of the EUV beam 22. The projection mirrors 238 may reflect thereflected portion of the EUV beam 22 to the substrate W. The reticle Rmay be contaminated by a material for generating the EUV beam 22 (e.g.,the material of the source drop 221). For example, the reticle R may becontaminated by particles 8. For example, the particles 8 may be metalnanoparticles of tin (Sn), xenon (Xe), titanium (Ti), or lithium (Li).

The substrate stage 250 may be disposed in a lower region of the innerspace of the main chamber 212. The substrate stage 250 may have asubstrate chuck 252. The substrate chuck 252 may receive the substrateW. The substrate chuck 252 may electrostatically hold the substrate W.The substrate W may be exposed to the EUV beam 22. A photoresist on thesubstrate W may be partially exposed to the EUV beam 22 along a patternof the reticle R.

The rapid exchange device 260 may be disposed between the first reticlestage 240 in the main chamber 212 and the auxiliary chamber 214. Therapid exchange device 260 may exchange the reticle R on the reticlechuck 242. The rapid exchange device 260 may transfer the reticle Rbetween the reticle chuck 252 and the auxiliary chamber 214.

FIG. 3 illustrates an embodiment of the reticle R of FIG. 2.

Referring to FIG. 3, the reticle R may be a reflective photomask. Insome embodiments, the reticle R may include a reticle substrate 2, areflective layer 4, and an absorption pattern 6.

The reticle substrate 2 may include quartz. Alternatively, the reticlesubstrate 2 may include a metal or a glass. However, embodiments of theinventive concepts are not limited thereto. The reticle substrate 2 mayhave a thickness of about 2 mm to about 5 mm.

The reflective layer 4 may be repeatedly stacked about 40 to 50 times onthe reticle substrate 2. The reflective layer 4 may reflect the EUV beam22. The reflective layer 4 may have a thickness of about 14 nm. Thereflective layer 4 may include a silicon layer 3 and a molybdenum layer5. The silicon layer 3 and the molybdenum layer 5 may be alternatelystacked on the reticle substrate 2.

The absorption pattern 6 may be disposed on the reflective layer 4. Theabsorption pattern 6 may absorb the EUV beam 22. The absorption pattern6 may include tantalum. The absorption pattern 6 may have a thickness ofabout 50 nm to about 60 nm.

FIG. 4 illustrates an embodiment of the reticle inspecting apparatus 40of FIG. 1.

Referring to FIG. 4, the reticle inspecting apparatus 40 may include areticle inspecting module 410 and a reticle cleaning module 420. Thereticle inspecting module 410 may be disposed at a side of the reticlecleaning module 420. The reticle inspecting module 410 may inspect theparticle 8 (see FIG. 5) of the reticle R. For example, the reticleinspecting module 410 may detect a defect (e.g., the particle 8 of FIG.5 and/or the void 9 of FIG. 11) of the reticle R. When the particle 8exists on the reticle R, the reticle cleaning module 420 may clean thereticle R to remove the particle 8. The reticle inspecting module 410,such as examples in FIGS. 4 and 7, may include an optical spectroscope,but is not limited thereto.

FIG. 5 illustrates an embodiment of the reticle inspecting module 410 ofFIG. 4.

Referring to FIG. 5, the reticle inspecting module 410 may include asecond reticle stage 412, a second laser 414, a half mirror 415, anobjective 416, an eyepiece 418, and a photodetector 419.

The second reticle stage 412 may receive the reticle substrate 2. Thesecond reticle stage 412 may have a substrate cooler 411. For example,the substrate cooler 411 may include a Peltier device. The substratecooler 411 may cool the reticle R.

The second laser 414 may generate a second laser beam 413. The secondlaser beam 413 may include ArF ultraviolet light (e.g., 193 nm). Thesecond laser 414 may provide the second laser beam 413 to the halfmirror 415.

The half mirror 415 may be disposed between the objective 416 and theeyepiece 418. The half mirror 415 may reflect the second laser beam 413to the objective 416.

The objective 416 may be disposed between the half mirror 415 and thesecond reticle stage 412. The objective 416 may irradiate the secondlaser beam 413 to the reflective layer 4 and the absorption pattern 6 ofthe reticle R. The second laser beam 413 may be focused on thereflective layer 4 and the absorption pattern 6. The focused secondlaser beam 413 may be reflected from the reflective layer 4 and theabsorption pattern 6 and then may be provided to the objective 416. Theobjective 416 may provide the reflected second laser beam 413 to thehalf mirror 415. The half mirror 415 may transmit the second laser beam413 to the eyepiece 418.

The eyepiece 418 may be disposed between the half mirror 415 and thephotodetector 419. The eyepiece 418 may focus the transmitted secondlaser beam 413 on the photodetector 419.

The type of photodetector 419 is not particularly limited and mayinclude an image sensor circuit, photodiode, CCD device for detectingdefects on a reticle, including an EUV reticle. In example embodiments,the reticle inspecting module 410 of FIG. 4 (or FIG. 7) may furtherinclude a controller 405 for controlling operations of the reticleinspecting module 410 in FIG. 4 (or air blowing device 417 in FIG. 7).

The photodetector 419 may receive the second laser beam 413, based on aportion of the second laser beam 413 reflected and/or scattered afterbeing irradiated onto the reticle R, and generate signals based onreceiving the second laser beam 413. As discussed below, the controller405, based on signals from the photodetector 419, may obtain and/orgenerate an image of the reticle R and determine whether a defect (e.g.,the particle 8) exists on the reticle R or not. Alternatively, thecontroller 405, based on signals from the photodetector 419, maydetermine whether the reticle R is damaged or not.

The controller 405 may include processing circuitry such as hardwareincluding logic circuits; a hardware/software combination such as aprocessor executing software; or a combination thereof. For example, theprocessing circuitry more specifically may include, but is not limitedto, a central processing unit (CPU), an arithmetic logic unit (ALU), adigital signal processor, a microcomputer, a field programmable gatearray (FPGA), a System-on-Chip (SoC), a programmable logic unit, amicroprocessor, application-specific integrated circuit (ASIC), etc. Thecontroller 405 may control the photodetector 419, second laser 414, andsubstrate cooler 411 in FIG. 4 (or air blowing device 417 in FIG. 7) togenerate the image of the reticle R (and/or portion thereof) based onthe reflected and/or scattered portion of the second laser beam 413 thatthe photodetector 419 receives when the second laser 414 irradiates thereticle R (and/or portion thereof) with the second laser beam 413.

As discussed below, based on the controller 405 controlling the reticleinspecting module 410 so the substrate cooler 411 in FIG. 4 (or airblowing device 417 in FIG. 7) cools the reticle R while the second laser414 irradiates the second laser beam 413 to the reticle R, thecontroller 405 may be transformed into a special-purpose controller 405that improves the functioning the reticle inspecting module 410. Thecontroller 405 may improve the functioning of the reticle inspectionmodule 410 because the power of the second laser beam 413 irradiated tothe reticle R may be increased without damaging the reticle R when thesubstrate cooler 411 in FIG. 4 or the air blowing device 417 in FIG. 7)cools the reticle R.

In example embodiments, the controller 405 may operate the reticleinspecting module 410 to determine whether a portion of the reticle R(e.g., the reflective layer 4) has one or more defects (e.g., theparticle 8 in FIG. 5 or the void 9 in FIG. 11) based on a scatteringintensity profile of the reticle image Rimage generated using signalsfrom the photodetector 419. For example, as shown in FIG. 17, thereticle image Rimage generated by the controller 405 using thephotodetector 419 may include levels of a scattering intensity parameterat corresponding locations (e.g., locations A, B, C) of the reticleimage Rimage. In some embodiments, the scattering intensity parameter ata corresponding location may be based on the detection signal thephotodetector 419 generates in response to the reflected and/orscattered portion of the second laser beam 413 that the photodetector419 receives as the second laser beam 413 irradiates the correspondinglocation of the reticle R. In other embodiments, the scatteringintensity parameter associated with a corresponding location of thereticle image Rimage may be based further on a relationship (e.g.,difference) between a reference detection signal for the correspondinglocation in a reference reticle image (not shown) and the detectionsignal of the photodetector 419 generates in response to the reflectedand/or scattered portion of the second laser beam 413 that thephotodetector 419 receives as the second laser beam 413 irradiates thecorresponding location of the reticle R.

In some embodiments, the controller 405, using signals from thephotodetector 419, may determine a defect of a first type (e.g., void 9in FIG. 11) exists in a portion of the reticle R (e.g., reflective layer4) in response to the scattering intensity parameter I being greaterthan or equal to a first threshold Th1 and less than or second thresholdTh2 (see location C); no defect exists in response to the scatteringintensity parameter I being less than or equal to the first thresholdTh1 and less than the second threshold (see location B); and a defect ofa second type (e.g., particle 8 in FIG. 5) exists in response to thescattering intensity parameter I being greater than or equal to a secondthreshold Th2 (see location A). However, inventive concepts are notlimited thereto.

For example, referring to FIGS. 4 and 7, the image of the reticle R mayhave a resolution proportional to power of the second laser beam 413. Inother words, a detection signal of the photodetector 419 may be inproportion to the power of the second laser beam 413, and a noise may bein proportion to a square root of the power of the second laser beam413. For example, a signal-to-noise (S/N) ratio of the photodetector 419may be increased in proportion to a ratio of the power of the secondlaser beam 413 to the square root of the power.

A portion of the second laser beam 413 may be absorbed in the reflectivelayer 4 and the absorption pattern 6. When the power of the second laserbeam 413 is increased, the reflective layer 4 of the reticle R may beexcessively heated to cause intermixing failure of the silicon layer 3and the molybdenum layer 5. When the intermixing failure occurs, areflectance of the EUV beam 22 (see FIG. 2) may be reduced in theexposure apparatus. According to some embodiments of the inventiveconcepts, the controller 405 may operate the substrate cooler 411 tocool the reticle substrate 2 and the reflective layer 4, and thus theS/N ratio may be increased and damage (e.g., the intermixing failure) ofthe reflective layer 4 may be reduced and/or minimized.

For example, an intermixing occurrence temperature of the silicon layer3 and the molybdenum layer 5 may be about 200 degrees Celsius. If thepower of the second laser beam 413 is 0.5 W/cm² or more, the siliconlayer 3 and the molybdenum layer 5 at room temperature (or normaltemperature, e.g., 15 degrees Celsius) may be heated to 200 degreesCelsius or more, thereby causing the intermixing failure. When the powerof the second laser beam 413 is about 0.49 W/cm², the reflective layer 4may be heated to about 200 degrees Celsius. The maximum value of thepower of the second laser beam 413 may be about 0.49 W/cm² with respectto the silicon layer 3 and the molybdenum layer 5 at the roomtemperature (e.g., 15 degrees Celsius).

When the substrate cooler 411 cools the reticle R, the maximum value ofthe power of the second laser beam 413 may be increased. When thesilicon layer 3 and the molybdenum layer 5 are cooled by about 18.5degrees Celsius and thus have a temperature of about −3.5 degreesCelsius, the maximum value of the power of the second laser beam 413 maybe increased by about 10%. In this case, the power of the second laserbeam 413 may be about 0.539 W/cm². When the silicon layer 3 and themolybdenum layer 5 are cooled by about 37 degrees Celsius and thus havea temperature of about −22 degrees Celsius, the maximum value of thepower of the second laser beam 413 may be increased by about 20%. Inthis case, the power of the second laser beam 413 may be about 0.588W/cm².

On the other hand, the reflective layer 4 may have a heat capacity whichdecreases as a temperature decreases. When the substrate cooler 411cools the reticle R, the heat capacity of the reflective layer 4 may bereduced. When the heat capacity of the reflective layer 4 is reduced, atemperature of the reticle R may increase more rapidly as the power ofthe second laser beam 413 increases. In addition, as the reflectivelayer 4 is cooled, an energy required for cooling the reflective layer 4may increase, so that a cooling rate of the reflective layer 4 may bereduced. When the cooling rate of the reflective layer 4 is reduced, thesubstrate cooler 411 may not easily cool the reflective layer 4 and thepower of the second laser beam 413 may not be increased.

FIG. 6 shows a heat capacity 80 of the reflective layer 4 and anincrease rate 90 of the power of the second laser beam 413, according toa temperature of the reticle R of FIG. 2.

Referring to FIG. 6, the heat capacity 80 of the reflective layer 4 maybe in proportion to the temperature, and the increase rate 90 of thepower of the second laser beam 413 may be in inverse proportion to thetemperature. As the temperature of the reflective layer 4 decreases, theheat capacity 80 of the reflective layer 4 may decrease and the increaserate 90 of the power of the second laser beam 413 may increase. When thetemperature of the reflective layer 4 decreases below about 145 kelvins(K) (e.g., −128 degrees Celsius), the heat capacity 80 of the reflectivelayer 4 may decrease rapidly. For example, a gradient of the heatcapacity 80 of the reflective layer 4 may be less than about 0.01 at atemperature of about 145 kelvins (K) or more and may be equal to orgreater than about 0.01 at a temperature of about 145 kelvins (K) toabout 50 kelvins (K). The reflective layer 4 may be easily cooled at atemperature of about 145 kelvins (K) or more but may not be easilycooled at a temperature of about 145 kelvins (K) or less. At atemperature of about 145 kelvins (K), the heat capacity 80 of thereflective layer 4 may be about 2.8 J/cm³K, and the increase rate 90 ofthe power of the second laser beam 413 may be about 77%. The power ofthe second laser beam 413 may be calculated as a sum of the maximumvalue (0.49 W/cm²) at the room temperature (288 kelvins (K) or 15degrees Celsius) and the increase rate 90 of 77% (0.38 W/cm²). As aresult, the power of the second laser beam 413 may be increased to about0.87 W/cm².

When the reflective layer 4 is cooled to 145 kelvins (K) or less, thepower of the second laser beam 413 may be increased to about 0.87 W/cm²or more. However, the heat capacity 80 of the reflective layer 4 may bereduced to easily cause the intermixing failure of the silicon layer 3and the molybdenum layer 5 of the reflective layer 4.

At the room temperature (e.g., 288 kelvins (K) or 15 degrees Celsius),the heat capacity 80 of the reflective layer 4 may be about 4 J/cm³K andthe increase rate 90 of the power of the second laser beam 413 may be0%. The maximum value (0.49 W/cm²) of the power of the second laser beam413 may be provided.

FIG. 7 illustrates an embodiment of the reticle inspecting module 410 ofFIG. 4.

Referring to FIG. 7, a second reticle stage 412 of a reticle inspectingmodule 410 may include an air blowing device 417. A back surface of thereticle substrate 2 received on the second reticle stage 412 may beexposed to the air blowing device 417. The air blowing device 417 may bea cooler for cooling the reticle substrate 2. The air blowing device417, under the control of the controller 405, may provide cooling air 41to the back surface of the reticle substrate 2 to cool the reflectivelayer 4 disposed on the reticle substrate 2. A second laser 414, a halfmirror 415, an objective 416, an eyepiece 418 and a photodetector 419may be the same as described with reference to FIG. 5.

FIG. 8 illustrates an embodiment of the reticle cleaning module 420 ofFIG. 4.

Referring to FIG. 8, the reticle cleaning module 420 may include a wetcleaning module such as a spin wet cleaning apparatus or a dip wetcleaning apparatus. Alternatively, the reticle cleaning module 420 mayinclude, but not limited to, a dry cleaning module. In some embodiments,the reticle cleaning module 420 may include a spin chuck 422, a cleaningsolution supply unit 424, and a cleaning solution nozzle 426. The spinchuck 422 may rotate the reticle R. The cleaning solution supply unit424 may supply a cleaning solution 428 to the cleaning solution nozzle426. The cleaning solution nozzle 426 may be disposed over the spinchuck 422. The cleaning solution nozzle 426 may be connected to thecleaning solution supply unit 424. The cleaning solution nozzle 426 mayprovide the cleaning solution 428 onto the reticle R to clean thereticle R.

A method for manufacturing a semiconductor device by using themanufacturing apparatus 100 described above will be describedhereinafter.

FIG. 9 illustrates a method for manufacturing a semiconductor device,according to some embodiments of the inventive concepts.

Referring to FIG. 9, a method for manufacturing a semiconductor deviceaccording to some embodiments of the inventive concepts may includemanufacturing a reticle R (S100), performing an exposure process (S200),inspecting the reticle R (S300), determining whether a particle 8 existsor not (S400), cleaning the reticle R when the particle 8 exists (S500),and storing the reticle R (S600).

First, the reticle R may be manufactured by the reticle manufacturingapparatus 30 (S100).

FIG. 10 illustrates the operation S100 of manufacturing the reticle R ofFIG. 2, according to some embodiments of the inventive concepts.

Referring to FIG. 10, the operation S100 of manufacturing the reticle Rmay include forming a reflective layer 4 (S110), inspecting thereflective layer 4 (S120), determining whether a defect exists in thereflective layer 4 or not (S130), etching the reflective layer 4 (S140),forming an absorption layer (S150), forming a photoresist (S160),inspecting the photoresist (S170), determining whether a defect existsin the photoresist or not (S180), removing the photoresist (S190),patterning the photoresist (S192), and forming an absorption pattern 6(S194).

Hereinafter, the operation S100 of manufacturing the reticle R will bedescribed in more detail.

FIGS. 11 to 13 are process cross-sectional views of the reticle R ofFIG. 3.

Referring to FIGS. 10 and 11, the thin layer depositing module of thereticle manufacturing apparatus 30 may form the reflective layer 4 onthe reticle substrate 2 (S110). The reflective layer 4 may include asilicon layer 3 and a molybdenum layer 5. The silicon layer 3 may beformed by a chemical vapor deposition (CVD) method. The molybdenum layer5 may be formed by a sputtering method or a CVD method.

Next, the reticle inspecting module 410 of the reticle inspectingapparatus 40 may inspect the reflective layer 4 (S120). The reflectivelayer 4 may be inspected by an optical inspection method. The reticleinspecting module 410 may obtain a surface image of the reflective layer4 to detect a defect. For example, the defect may include a particle 8(see FIG. 5). Alternatively, the defect may include, but not limited to,a void 9 (see FIG. 11), a bump or a pit of the reflective layer 4.

FIG. 14 illustrates the operation S120 of inspecting the reflectivelayer 4 of FIG. 3, according to some embodiments of the inventiveconcepts.

Referring to FIG. 14, the reticle substrate 2 may be loaded on thesecond reticle stage 412 (S122). An interface device (not shown) mayprovide the reticle substrate 2 onto the second reticle stage 412. Thereticle substrate 2 may be provided on the substrate cooler 411 of thesecond reticle stage 412.

Next, the reticle substrate 2 may be cooled by the substrate cooler 411(S124). The substrate cooler 411 may cool the reticle substrate 2 to atemperature lower than the room temperature. For example, the substratecooler 411 may cool the reticle substrate 2 to about 145 kelvins (K).The reflective layer 4 may be cooled to a temperature equal to thetemperature of the reticle substrate 2.

Subsequently, the second laser 414 may irradiate the second laser beam413 to the reflective layer 4 (S126). For example, in the operation S120of inspecting the reflective layer 4, the power of the second laser beam413 may be increased using the operation S124 of cooling the reticlesubstrate 2. The power of the second laser beam 413 may be about 0.49W/cm² or more. For example, the second laser 414 may provide the secondlaser beam 413 having the power of about 0.87 W/cm². The second reticlestage 412 may move the reticle substrate 2 to scan the second laser beam413 on the reflective layer 4. For example, the second laser beam 413may include ArF ultraviolet light having a wavelength of about 193 nm.The second laser beam 413 may be scanned at a speed of about 12.3 mm/s.

The photodetector 419 may receive the second laser beam 413 and providea signal to the controller 405 to detect a defect of the reflectivelayer 4 (S128). Since the power of the second laser beam 413 isincreased, based on the signal from the photodetector 419, thecontroller 405 may obtain a surface image of the reflective layer 4,which has an excellent S/N ratio. In addition, controller 405 may usethe signal from the photodetector 419 to detect the defect of thereflective layer 4 by using the surface image. A kind of the defect ofthe reflective layer 4 may be various. For example, the defect of thereflective layer 4 may include the particle 8. When the particle 8 isthe defect of the reflective layer 4, the reticle cleaning module 420 ofthe reticle inspecting apparatus 40 may clean the reticle R to removethe particle 8. Alternatively, the defect of the reflective layer 4 mayinclude a void 9 (see FIG. 11) of the reflective layer 4. Hereinafter,the defect of the reflective layer 4 which is the void 9 of FIG. 11 willbe described.

Referring again to FIG. 10, the reticle inspecting apparatus 40 maydetermine whether the defect exists in the reflective layer 4 or not(S130). For example, referring to FIG. 17, in an embodiment, thecontroller 405 may obtain a reticle image Rimage of the reflective layerusing the photodetector 419 in FIGS. 5 and 7. The controller 405, usingsignals from the photodetector 419, may determine a defect of a firsttype (e.g., void 9 in FIG. 11) exists in a portion of the reticle R(e.g., reflective layer 4) in response to the scattering intensityparameter I being greater than or equal to a first threshold Th1 andless than or second threshold Th2 (see location C); no defect exists inresponse to the scattering intensity parameter I being less than orequal to the first threshold Th1 and less than the second threshold (seelocation B); and a defect of a second type (e.g., particle 8 in FIG. 5)exists in response to the scattering intensity parameter I being greaterthan or equal to a second threshold Th2 (see location A). However,inventive concepts are not limited thereto.

When (and/or in response to) the defect exists in the reflective layer4, the etching module of the reticle manufacturing apparatus 30 may etchthe reflective layer 4 (S140). Thus, the reflective layer 4 may beremoved from the reticle substrate 2. Thereafter, the operation S110 offorming the reflective layer 4, the operation S120 of inspecting thereflective layer 4, and the operation S130 of determining whether thedefect exists in the reflective layer 4 or not may be repeated.

Referring to FIGS. 10 and 12, when the defect does not exist in thereflective layer 4, the thin layer depositing module of the reticlemanufacturing apparatus 30 may form the absorption layer 7 on thereflective layer 4 (S150). The absorption layer 7 may include tantalumformed by a sputtering method or a layer having the tantalum.

Referring to FIGS. 10 and 13, the photoresist coating module of thereticle manufacturing apparatus 30 may form a photoresist PR on theabsorption layer 7 (S160). The photoresist PR may be coated by a spincoating method.

Next, the reticle inspecting module 410 of the reticle inspectingapparatus 40 may inspect the photoresist PR (S170). The photoresist PRmay be inspected by an optical inspection method. The operation S170 ofinspecting the photoresist PR may be a operation of inspecting thephotoresist PR and the absorption layer 7.

FIG. 15 illustrates the operation S170 of inspecting the photoresist PRof FIG. 13, according to some embodiments of the inventive concepts.

Referring to FIG. 15, the operation S170 of inspecting the photoresistPR may be similar to the operation S120 of inspecting the reflectivelayer 4.

The reticle substrate 2 may be loaded on the second reticle stage 412 ofthe reticle inspecting module 410 (S172). An interface device mayprovide the reticle substrate 2 on the substrate cooler 411 of thesecond reticle stage 412.

Next, the reticle substrate 2 may be cooled by the substrate cooler 411(S174). For example, the substrate cooler 411 may cool the reticlesubstrate 2 to about 145 kelvins (K) lower than the room temperature.

Subsequently, the second laser 414 may irradiate the second laser beam413 to the photoresist PR (S176). For example, in the operation S170 ofinspecting the photoresist PR, the power of the second laser beam 413may be increased using the operation S174 of cooling the reticlesubstrate 2. The power of the second laser beam 413 may be about 0.49W/cm² or more. The second laser 414 may provide the second laser beam413 having the power of about 0.87 W/cm². The second laser beam 413 mayinclude ArF ultraviolet light having a wavelength of about 193 nm. Thesecond laser beam 413 may be scanned at a speed of about 12.3 mm/s. Thesecond laser beam 413 may be provided without chemical modification andphysical deformation of the photoresist PR. The photoresist PR may havephotosensitivity with respect to light having a wavelength in an EUVrange (e.g., 13.5 nm). For example, the second laser beam 413 may have awavelength in an ultraviolet range (e.g., 193 nm) to a visible lightrange (e.g., 700 nm), and the photosensitivity of the photoresist PR maybe reduced and/or minimized.

The controller 405 may control the photodetector 419 to receive thesecond laser beam 413 to detect a defect of the photoresist PR (S178).The controller 405 may use photodetector 419 to obtain an image of thephotoresist PR. The defect of the photoresist PR may include a void 9 ora particle 8.

Referring again to FIG. 10, the reticle inspecting apparatus 40 maydetermine whether the defect exists in the photoresist PR or not (S180).

For example, referring to FIG. 17, in an embodiment, the controller 405may determine whether the defect exists in the photoresist using aoperation that is similar to determining whether the defect exists inthe reflective layer, except the reticle image Rimage is made for thephotoresist PR. The controller 405 may obtain a reticle image Rimage ofthe photoresist using the photodetector 419 in FIGS. 5 and 7. Thecontroller 405, using signals from the photodetector 419, may determinea defect of a first type (e.g., void 9 in FIG. 11) exists in a portionof the reticle R (e.g., photoresist) in response to the scatteringintensity parameter I being greater than or equal to a first thresholdTh1 and less than or second threshold Th2 (see location C); no defectexists in response to the scattering intensity parameter I being lessthan or equal to the first threshold Th1 and less than the secondthreshold (see location B); and a defect of a second type (e.g.,particle 8 in FIG. 5) exists in response to the scattering intensityparameter I being greater than or equal to a second threshold Th2 (seelocation A). However, inventive concepts are not limited thereto.

When the defect exists in the photoresist PR, the photoresist PR may beremoved by an ashing apparatus or a cleaning apparatus (S190).Thereafter, the operation S160 of forming the photoresist PR, theoperation S170 of inspecting the photoresist PR, and the operation S180of determining whether a defect exists in the photoresist PR or not maybe repeated.

When the defect does not exist in the photoresist PR, thephotolithography module of the reticle manufacturing apparatus 30 maypattern the photoresist PR (S192).

Referring to FIGS. 3 and 10, the absorption layer may be etched usingthe patterned photoresist PR as an etch mask by the etching module toform the absorption pattern 6 (S194). The photoresist PR may be removed.The process for manufacturing the reticle R may be completed, and then,the reticle R may be provided into the exposure apparatus 20.

Referring again to FIG. 9, the exposure apparatus 20 may perform theexposure process on a substrate W by using the reticle R (S200). In someembodiments, the reticle R may include an EUV reticle, and the exposureprocess may include an EUV exposure process. When the exposure processis performed for a certain time or failure of the exposure processoccurs, the reticle R may be replaced.

Next, the reticle R may be inspected by the reticle inspecting apparatus40 (S300).

FIG. 16 illustrates the operation S300 of inspecting the reticle R ofFIG. 3, according to some embodiments of the inventive concepts.

Referring to FIG. 16, the operation S300 of inspecting the reticle R maybe similar to the operation S120 of inspecting the reflective layer 4and the operation S170 of inspecting the photoresist PR.

The reticle substrate 2 of the reticle R may be loaded on the secondreticle stage 412 (S310). The reticle substrate 2 may be provided on thesubstrate cooler 411.

Next, the substrate cooler 411 may cool the reticle substrate 2 (S320).The substrate cooler 411 may cool the reticle substrate 2 to atemperature lower than the room temperature. For example, the substratecooler 411 may cool the reticle substrate 2 to about 145 kelvins (K).The reflective layer 4 and the absorption pattern 6 may be cooled to atemperature equal to the temperature of the reticle substrate 2.

Subsequently, the second laser 414 may irradiate the second laser beam413 to the reflective layer 4 and the absorption pattern 6 (S330). Forexample, in the operation S300 of inspecting the reticle R, the power ofthe second laser beam 413 may be increased using the operation S320 ofcooling the reticle substrate 2. The power of the second laser beam 413may be about 0.49 W/cm² or more. For example, the second laser 414 mayprovide the second laser beam 413 having the power of about 0.87 W/cm².The second laser beam 413 may include ArF ultraviolet light having awavelength of about 193 nm. The second laser beam 413 may be scanned ata speed of about 12.3 mm/s.

The photodetector 419 may receive the second laser beam 413 to detect aparticle 8 on the reflective layer 4 and the absorption pattern 6(S340). The photodetector 419 may obtain a surface image of thereflective layer 4 and the absorption pattern 6 of the reticle R, whichhas an excellent S/N ratio. In addition, the photodetector 419 maydetect the particle 8 by using the surface image.

Referring again to FIG. 9, the reticle inspecting apparatus 40 maydetermine whether the particle 8 exists on the reticle R or not (S400).

When the particle 8 exists on the reticle R, the reticle R may becleaned by the reticle cleaning module 420 (S500). The reticle R may becleaned by a wet cleaning method. Thereafter, the operation S300 ofinspecting the reticle R and the operation S400 of determining whetherthe particle 8 exists on the reticle R or not may be repeated.

When the particle 8 does not exist on the reticle R, the reticle R maybe stored in the reticle storing apparatus 50 (S600). A nitrogen (N2)gas may be provided to the reticle R in the reticle storing apparatus50. The nitrogen gas may prevent oxidation of the reticle R.

In the method for inspecting a reticle according to the embodiments ofthe inventive concepts, the reticle substrate may be cooled to increasethe S/N ratio of the optical inspection and to reduce and/or minimizedamage of the reflective layer of the reticle.

While the inventive concepts have been described with reference toexample embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirits and scopes of the inventive concepts. Therefore, itshould be understood that the above embodiments are not limiting, butillustrative. Thus, the scopes of the inventive concepts are to bedetermined by the broadest permissible interpretation of the followingclaims and their equivalents, and shall not be restricted or limited bythe foregoing description.

What is claimed is:
 1. A method for inspecting a reticle, the methodcomprising: loading the reticle on a stage, the reticle including areticle substrate and a reflective layer on the reticle substrate;cooling the reticle substrate; irradiating a laser beam to thereflective layer on the reticle substrate; receiving the laser beamusing a photodetector to obtain an image of the reflective layer; anddetecting whether a particle defect exists on the reflective layer or avoid defect exists in the reflective layer based on the image of thereflective layer, wherein the reticle substrate is cooled below 145kelvins (K) to decrease a specific heat capacity of the reflective layerand to increase a power of the laser beam.
 2. The method of claim 1,wherein the laser beam has power of 0.87 W/cm².
 3. The method of claim1, wherein the laser beam includes ArF ultraviolet light.
 4. The methodof claim 1, wherein the laser beam is scanned at a speed of 12.3 mm/s.5. The method of claim 1, wherein the reticle includes an extremeultraviolet (EUV) reticle.
 6. The method of claim 5, wherein thereflective layer of the EUV reticle includes a molybdenum layer on asilicon layer.
 7. The method of claim 5, wherein the EUV reticle furtherincludes an absorption pattern on the reflective layer.
 8. The method ofclaim 1, wherein the stage includes a cooler for cooling the reticlesubstrate.
 9. The method of claim 8, wherein the cooler includes aPeltier device or an air blowing device.